<?php  if ( ! defined('BASEPATH')) exit('No direct script access allowed');

class Recaptcha {
/*
 * This is a PHP library that handles calling reCAPTCHA.
 *    - Documentation and latest version
 *          http://recaptcha.net/plugins/php/
 *    - Get a reCAPTCHA API Key
 *          https://www.google.com/recaptcha/admin/create
 *    - Discussion group
 *          http://groups.google.com/group/recaptcha
 *
 * Copyright (c) 2007 reCAPTCHA -- http://recaptcha.net
 * AUTHORS:
 *   Mike Crawford
 *   Ben Maurer
 * 
 * CONTRIBUTION: 
 * Codeigniter version - 23.08.2012 by Christer Nordbø, Norway.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

/**
 * The reCAPTCHA server URL's
 */
    
    const RECAPTCHA_API_SERVER = "http://www.google.com/recaptcha/api";
    const RECAPTCHA_API_SECURE_SERVER = "https://www.google.com/recaptcha/api";
    const RECAPTCHA_VERIFY_SERVER = "www.google.com";
    
    
    var $is_valid;
    var $error;
    
    //Remember to obtain the Public and Private key @ https://www.google.com/recaptcha/admin/create
    var $public_key = "6Lc6wd4SAAAAAJGU7_GJVIZECkIziRaB2BSm5ozu";
    var $privkey = "6Lc6wd4SAAAAAHqtkc4aNVofhyADPjU9oBxCgg5Z";
    

    /**
    * Encodes the given data into a query string format
    * @param $data - array of string elements to be encoded
    * @return string - encoded request
    */
    function recaptcha_qsencode ($data) {
            $req = "";
            foreach ( $data as $key => $value )
                    $req .= $key . '=' . urlencode( stripslashes($value) ) . '&';

            // Cut the last '&'
            $req=substr($req,0,strlen($req)-1);
            return $req;
    }



    /**
    * Submits an HTTP POST to a reCAPTCHA server
    * @param string $host
    * @param string $path
    * @param array $data
    * @param int port
    * @return array response
    */
    function recaptcha_http_post($host, $path, $data, $port = 80) {

            $req = $this->recaptcha_qsencode ($data);

            $http_request  = "POST $path HTTP/1.0\r\n";
            $http_request .= "Host: $host\r\n";
            $http_request .= "Content-Type: application/x-www-form-urlencoded;\r\n";
            $http_request .= "Content-Length: " . strlen($req) . "\r\n";
            $http_request .= "User-Agent: reCAPTCHA/PHP\r\n";
            $http_request .= "\r\n";
            $http_request .= $req;

            $response = '';
            if( false == ( $fs = @fsockopen($host, $port, $errno, $errstr, 10) ) ) {
                    die ('Could not open socket');
            }

            fwrite($fs, $http_request);

            while ( !feof($fs) )
                    $response .= fgets($fs, 1160); // One TCP-IP packet
            fclose($fs);
            $response = explode("\r\n\r\n", $response, 2);

            return $response;
    }



    
    function recaptcha_get_html ($error = null, $use_ssl = false)
    {
            if ($this->public_key == null || $this->public_key == '') {
                    die ("To use reCAPTCHA you must get an API key from <a href='https://www.google.com/recaptcha/admin/create'>https://www.google.com/recaptcha/admin/create</a>");
            }

            if ($use_ssl) {
                    $server = self::RECAPTCHA_API_SECURE_SERVER;
            } else {
                    $server = self::RECAPTCHA_API_SERVER;
            }

            $errorpart = "";
            if ($error) {
            $errorpart = "&amp;error=" . $error;
            }
            return '<script type="text/javascript" src="'. $server . '/challenge?k=' . $this->public_key . $errorpart . '"></script>

            <noscript>
                    <iframe src="'. $server . '/noscript?k=' . $this->public_key . $errorpart . '" height="300" width="500" frameborder="0"></iframe><br/>
                    <textarea name="recaptcha_challenge_field" rows="3" cols="40"></textarea>
                    <input type="hidden" name="recaptcha_response_field" value="manual_challenge"/>
            </noscript>';
    }







    /**
    * Calls an HTTP POST function to verify if the user's guess was correct
    * @param string $remoteip
    * @param string $challenge
    * @param string $response
    * @param array $extra_params an array of extra variables to post to the server
    * @return ReCaptchaResponse
    */
    function recaptcha_check_answer ($remoteip, $challenge, $response, $extra_params = array())
    {
            if ($this->privkey == null || $this->privkey == '') {
                    die ("To use reCAPTCHA you must get an API key from <a href='https://www.google.com/recaptcha/admin/create'>https://www.google.com/recaptcha/admin/create</a>");
            }

            if ($remoteip == null || $remoteip == '') {
                    die ("For security reasons, you must pass the remote ip to reCAPTCHA");
            }



            //discard spam submissions
            if ($challenge == null || strlen($challenge) == 0 || $response == null || strlen($response) == 0) {
                    
                    $this->is_valid = false;
                    $this->error = 'incorrect-captcha-sol';
                    
            }

            $response = $this->recaptcha_http_post (self::RECAPTCHA_VERIFY_SERVER, "/recaptcha/api/verify",
                                            array (
                                                    'privatekey' => $this->privkey,
                                                    'remoteip' => $remoteip,
                                                    'challenge' => $challenge,
                                                    'response' => $response
                                                    ) + $extra_params
                                            );

            $answers = explode ("\n", $response [1]);
            

            if (trim ($answers [0]) == 'true') {
                    $this->is_valid = true;
            }
            else {
                    $this->is_valid = false;
                    $this->error = $answers [1];
            }
            

    }

    /**
    * gets a URL where the user can sign up for reCAPTCHA. If your application
    * has a configuration page where you enter a key, you should provide a link
    * using this function.
    * @param string $domain The domain where the page is hosted
    * @param string $appname The name of your application
    */
    function recaptcha_get_signup_url ($domain = null, $appname = 'Codeigniter') {
            return "https://www.google.com/recaptcha/admin/create?" .  $this->recaptcha_qsencode (array ('domains' => $domain, 'app' => $appname));
    }

    function recaptcha_aes_pad($val) {
            $block_size = 16;
            $numpad = $block_size - (strlen ($val) % $block_size);
            return str_pad($val, strlen ($val) + $numpad, chr($numpad));
    }

    /* Mailhide related code */

    function recaptcha_aes_encrypt($val,$ky) {
            if (! function_exists ("mcrypt_encrypt")) {
                    die ("To use reCAPTCHA Mailhide, you need to have the mcrypt php module installed.");
            }
            $mode=MCRYPT_MODE_CBC;   
            $enc=MCRYPT_RIJNDAEL_128;
            $val=$this->recaptcha_aes_pad($val);
            return mcrypt_encrypt($enc, $ky, $val, $mode, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0");
    }


    function recaptcha_mailhide_urlbase64 ($x) {
            return strtr(base64_encode ($x), '+/', '-_');
    }

    /* gets the reCAPTCHA Mailhide url for a given email, public key and private key */
    function recaptcha_mailhide_url($email) {
            if ($this->public_key == '' || $this->public_key == null || $this->privkey == "" || $this->privkey == null) {
                    die ("To use reCAPTCHA Mailhide, you have to sign up for a public and private key, " .
                        "you can do so at <a href='http://www.google.com/recaptcha/mailhide/apikey'>http://www.google.com/recaptcha/mailhide/apikey</a>");
            }


            $ky = pack('H*', $this->privkey);
            $cryptmail = $this->recaptcha_aes_encrypt ($email, $ky);

            return "http://www.google.com/recaptcha/mailhide/d?k=" . $this->public_key . "&c=" . $this->recaptcha_mailhide_urlbase64 ($cryptmail);
    }

    /**
    * gets the parts of the email to expose to the user.
    * eg, given johndoe@example,com return ["john", "example.com"].
    * the email is then displayed as john...@example.com
    */
    function recaptcha_mailhide_email_parts ($email) {
            $arr = preg_split("/@/", $email );

            if (strlen ($arr[0]) <= 4) {
                    $arr[0] = substr ($arr[0], 0, 1);
            } else if (strlen ($arr[0]) <= 6) {
                    $arr[0] = substr ($arr[0], 0, 3);
            } else {
                    $arr[0] = substr ($arr[0], 0, 4);
            }
            return $arr;
    }

    /**
    * Gets html to display an email address given a public an private key.
    * to get a key, go to:
    *
    * http://www.google.com/recaptcha/mailhide/apikey
    */
    function recaptcha_mailhide_html($email) {
            $emailparts = $this->recaptcha_mailhide_email_parts ($email);
            $url = $this->recaptcha_mailhide_url ($this->public_key, $this->privkey, $email);

            return htmlentities($emailparts[0]) . "<a href='" . htmlentities ($url) .
                    "' onclick=\"window.open('" . htmlentities ($url) . "', '', 'toolbar=0,scrollbars=0,location=0,statusbar=0,menubar=0,resizable=0,width=500,height=300'); return false;\" title=\"Reveal this e-mail address\">...</a>@" . htmlentities ($emailparts [1]);

    }


}

?>
